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MPPA PCB Components

PCB Top Parts overview

MPPA top parts overview as PDF

MPPA top parts overview

MPPA bottom parts as PDF

MPPA bottom parts overview

Toroid core and Transformers

The winding of the toroid cores are realy easy see our examples.

Inductor L12 23µH Core FT37-43

The circuit diagram shows "FT37-43, 23µH 9T, 0.5CuL/270deg" that means:
Use Toroid FT37-43, wind 9 turns with 0.5mm wire over 270° degrees.

First wind 9 Turns 0.5CuL over 270 Degrees


As next bend the wire as shown


Solder the Inductor L12


Driver Transformer L6 BN43-202 Core

The circuit diagram shows "Primary: 0.5CuL 2+2 Turns / Secondary: 0.5CuL 3 Turns" that means:
Use core BN43-202, wind primary 2+2 turns with 0.5mm wire.
As next wind secondary 3 turns with 0.5mm wire.

First twist and solder the wire as shown

twist and solder the wire

As next wind primary 2+2 turns



Now wind the secondary 3 turns


Solder the Driver Transformer L6


Output Transformer L11 BN43-202 Core

The circuit diagram shows "Primary: 3x0.5CuL twisted 1+1 Wdg = 9.8µH / Secondary: 0.8CuL 3 Wdg =22.4µH" that means:
Use core BN43-202, take three wires 0.5mm CuL and twist them to a primary wire you need twice of them.
Solder the end of the twice primary wires as the picture below.
Now made the primary 1+1 turn.
As next wind secondary 3 turns with 0.8mm wire.

First twist the wire as shown

twist the wire

Now solder two twisted wires

two twisted wires

Wind primary 1+1 turns

primary 1+1

Wind the secondary 3 turns with 0.8 CuL

secondary 3 turns

Solder the output transformer L11

output transformer

Driver and PA bias alignment

Bias adjust procedure of the standby current driver and PA.

During the adjustment of the MPPA use a dummy load on Bu3 RX/TX.
You need a adjustable powersupply with a current limiter. (12VDC max. 500mA)
A good current measurement device to measure the current at JP1 and JP2.

  • First open JP1 and JP2
  • Turn all bias driver trimmer to the ground side, to be save measure it!
  • Power up the preselector with the mppa, controlling the max. current!.
  • Measure the current at JP1 and adjust driver T1 RD01MUS2 with trimmer R5 to 65mA
  • Now adjust driver T2 RD01MUS2 trimmer R6 up to 130mA
  • As next measure the current at JP2 and adjust output driver T2 RD07MVS1 with trimmer R14 to 165mA
  • Adjust output driver T4 RD07MVS1 with trimmer R15 up to 330mA.
  • Close JP1 and JP2

Now the alignment is done and the complete current of preselector with mppa should be during transmitting at max. 2100mA.

Standby Current Ub=12V
Driver Part FET Current Setpoint Testpoint
Driver Bias 1 T1 RD01MUS2 65mA R5 JP1
Driver Bias 2 T2 RD01MUS2 65mA R6 JP1
Driver Bias 1 T3 RD07MVS1B 165mA R14 JP2
Driver Bias 2 T4 RD07MVS1B 165mA R15 JP2

MPPA Trimm adjust